Alaskan frogs can come back from the dead

You're frozen solid, your heart's stopped beating, and you haven't breathed in days. You're dead, right? Not if you're an Alaskan wood frog. The amphibian -- an Arctic population of the wood frog, Rana sylvatica -- can tolerate being frozen, heart and respiration both stopped, for days or even weeks at a time. Scientists found that they could survive temperatures down to 3.2 degrees Fahrenheit, while they're Midwestern cousins could only come back from a balmy 24.8 degrees Fahrenheit. All of which is super cool, of course, but it has a practical, and potentially human-lifesaving application, as well. From National Geographic:

Beyond being fascinating science, the ability to freeze and unfreeze living organs and tissues without damaging them has potentially profound implications for areas such as organ transplantation. “There’s an obvious parallel between what these frogs are doing to preserve all of their tissues simultaneously and our need to be able to cryopreserve human organs for tissue-matching purposes,” said [researcher Jon] Costanzo, noting that attempts to successfully freeze human organs for transplants have so far proved unsuccessful, perhaps due to their relative size and cellular complexity. “If you could freeze human organs even for a short period of time, that would be a major breakthrough because then these organs could be shipped around the world, which would greatly [improve] the donor-matching process,” noted Costanzo.

Read the rest here. Photo: A wood frog in New Jersey, by kingsnake.com user BryanD.